Throttling device



Feb. 8, 1944. w. E. SLOAN THROTTLING DEVICE Filed March 8, 1938IIIIIIIIIII INVENTOR gg/5 54mm ATTORNEY Patented Feb. 8, 1944 THROTTLINGDEVIGE William E. Sloan, River Forest, 111., assignor to Sloan ValveCompany,-Chicago, 111., a corporation of Illinois Application Marsh 8,1938, Serial No. 194,633

2 Claims.

The present invention relates to throttling devices, and has for itsmain object the production of new and improved devices which will permitof the quiet throttling of a relatively high rate of flow from ahigh-pressure source of liquid.

In carrying out the objects of the invention, a throttling device hasbeen produced in which the liquid is caused to flow betweensubstantially parallel roughened surfaces which are caused to overlapone another more or less ac cording to the supply pressure and thedesired rate of flow. One of the roughened surfaces is preferably theinside surface of a cylindrical water passage, the other and cooperatingroughened surface being the outside surface of a plug or cylinder whichis adjustable more or less within the first-mentioned roughened surface.The diameter of the plug is preferably less than the inside diameter ofthe passageway by several thousandths of an inch, whereby the liquidflows in a. thin annular sheet between the two roughened surfaces, thevelocity of the annular sheet being thereby retarded by each of the tworoughened surfaces between which the annular sheet of liquid passes.

Experience has indicated that, whatever the explanation for the noiseproduced by the flow of water from high pressure to low pressure, thegeneration of noise is always accompanied by a relatively high velocity.The quiet throttling action of the devices herein illustrated,constructed according to the present invention, is believed to bederived largely from the reduction in velocity of the flowing liquid toa point below the critical noise-making velocity.

With respect to the form which the roughening of the two cooperatingsurfaces takes, standard screw threads have been found to besatisfactory, as well as standard forms of knurling, such as that of thewell-known diamond knurl. The roughening on both surfaces may be thesame, or one surface may be roughened by threading, while thecooperating surface is roughened by diamond knurling. The choice of oneor the other form of roughening depends largely upon manufacturing andsize considerations, keeping in mind such things as ratio of length ofoverlap to the mean diameter of the cooperating roughened surfaces.

A feature of the invention herein illustrated is that the desired rateof flow may be secured from lower pressures by merely reducing theoverlap the required amount. The overlap of the two roughened surfacesis entirely eliminated, and the minimum area through the throttlingdevice is greatly enlarged, by withdrawing the plug entirely from thecooperating passageway. Effective Silencing in the zone of transitionfrom overlap to no overlap is produced by slightly flaring the entranceto the passageway, as well as by silghtly tapering or rounding thecooperating end of the plug.

Other objects and features of the invention will become more apparentupon a further perusal of the specification.

Referring now to the accompanying drawing, comprising Figs. 1 to 7, theyshow sufficient views of devices constructed according to the featuresof the invention to enable the invention to be understood.

Figures 1 and 2 show a small-scale top view and front view,respectively, of a flush valve installation wherein the improved quietthrottling device 3 is inserted between the usual stop or valve 2 andthe flush valve 4;

Figure 3 is a full-scale sectional View of the improved quiet throttlingdevice 3 illustrated in Figs. 1 and 2; 7

Figures 4 and 5 show a small-scale top view and front view of a flushvalve installation wherein the controlling stop of conventional designhas been'replaced by an improved quiet throttling stop valve .32;

Figure 6 is a full-scale sectional view of the quiet throttling stopI82, shown in full in Figs. 4 and 5; and

Figure '7 is an enlarged view of the lower righthand corner of thenipple or tail-piece [5 of the throttling device 3, Fig. 5, illustratingthe thread form used on the inside surface.

Referring now particularly to Figs. 1 and 2, in the illustratedinstallation the supply pipe I extends through a wall to the inlet ofthe stop or shut-off valve 2, the exit of the supply pipe from the wallbeing covered by the usual Wall flange l. The outlet of the stop Zisconnected by the usual tail-piece and ground-joint union to the inlet 52of the quiet throttling device 3. In turn, the outlet E5 of the quietthrottling device 3 is screw-threaded into the inlet of the flush valvel. The discharge tube 6 is connected to the outlet of the flush valve lto carry water to the receptacle to be flushed, the flushing actionbeing initiated by an operation of the handle 5' of the flush valve.

In this installation, the stop 2 is used to shut off the supply entirelywhen either the throttling device 3 or the flush valve l is to beinspected or repaired, being turned wide open for regular operation. Therate of flow of water through the flush valve 4 and discharge tube 6 tothe receptacle to be flushed is regulated by a suitable adjustment ofthe throttling device 3.

Referring now particularly to Fig. 3, the construction of the throttlingdevice 3 will now be described in detail. The casing H has the form andgeneral dimensions of a 1-inch T fitting, the inlet opening being at ii,the outlet opening at 13, and the bonnet opening at M. The inlet openingI2 is inside-threaded in the usual mans ner to receive either a standard1-inch pipe or nipple. The outlet opening l3 and the bonnet opening 14are outside threaded to enable the outlet tail-piece l5 and the bonnet[8 to be secured in place by coupling nuts 20 and IS.

The inside surface of the outlet tail-piece I5 is roughened byscoring-which may conveniently take the form of the thread cut by astandard threading tool. The thread chosen is preferably one with a fiattop, as is illustrated best in Fig. '7, an enlarged showing of the lowerright-hand corner of the outlet piece iii. The entrance to the outletpiece I5 is preferably flared as illustrated, and this flared portionpreferably has its surface roughened by scoring.

Although the form of the thread used and the number of threads to theinch has not been found to be critical, a thread form similar to that ofBriggs standard pipe thread, particularly as customarily modified togive a comparatively sharp bottom and a comparatively flat top issatisfactory. The efficiency, however, is increased somewhat byarranging the cutting tool so that the width of the fiat on the top ofthe thread is somewhat greater than is commonly used, approaching theproportion of fiat used in an acme thread. It seems to be immaterialwhether the bottom of the thread is flat or sharp.

Variable throttling is produced by the throttle piece or cylindricalplug l6, fixed to the adjustable stem ll. The stem I1 is screw-threadedinto the bonnet l8. A water-tight connection with the smooth outer endof the stem H is maintained by the packing 2|, held in place by thepacking nut 22.

The surface of the adjustable plug it is rough encd by diamond knurlingas illustrated, there being about thirty elevations to the inch in thedirection of flow, separated by a corresponding number of valleys.

As illustrated, there is a substantial clearance between the surface ofthe plug l6 and the inside surface of the discharge piece l5, wherebythe liquid passing through the device in the illustrated position ofadjustment takes the form of an annular sheet or tube at the point ofgreatest restriction. For the purpose illustrated, there may be aclearance between the plug l6 and the inside of the barrel l5 of about.020 inch on each side, there being a total difference in diameter ofabout .040 inch. With this clearance, and with the roughened surfacesillustrated and described hereinbefore, a quiet rate of flow of fromtwelve to fourteen gallons a minute can be secured from a high pressuresource with the plug l5 adjusted into the discharge piece 5 to give anoverlap of between inch and A; inch of the straight portion at apressure of thirty pounds to the square inch, the overlap beingincreased about inch for each ten pounds increase in supplied pressure.When this is carried out, it will be found that an overlap of about inchto one inch gives a rate of flow of between twelve and fourteen gallonsa minute at a line pressure of one hundred pounds. The illustrated plugl6 and cooperating barrel are of such length that a quiet discharge oftwelve to fourteen gallons a minute can be obtained from line pressuresapproaching two hundred pounds to the square inch.

In order to obtain a rate of flow of from twelve to fourteen gallons aminute quietly from a supplied pressure of less than thirty pounds tothe square inch, the overlap of between inch and inch used at aboutthirty pounds pressure is correspondingly decreased, the straightportion of the overlap being lost entirely at a pressure of from twentyto twenty-five pounds to the square inch. At such a pressure, thetapered or rounded forward end of the plug I6 is Within the taperedentrance to the inside-threaded piece [5, and the throttling is thenperformed between the conical surface of the flared entrance to the partl5 and the correspondingly shaped end of the throttle piece l6. Forpressures on down to about fifteen pounds to the square inch, verylittle length is required in the throttling restriction to providesilence, as the maximum velocity which can be obtained at a pressure offifteen pounds is just at or below the critical noisemaking velocity.Experiment has demonstrated rather conclusively that no objectionablenoises are produced with any form of throttling device when the pressureis at or below fifteen pounds to the square inch.

For very low pressures, the piece I6 may be withdrawn entirely from thevicinity of the entrance to the outlet piece 15, giving a fullunrestricted one-inch waterway.

As previously discussed, the device illustrated in detail in Fig. 3, andillustrated in an installation in Figs. 1 and 2, is capable of giving aquiet rate of flow up to twelve to fourteen gallons 9. minute from asupply pressure high enough to generate objectionable noise if notproperly throttled. This rate of flow is ample to flush manyreceptacles, such as most forms of urinals, and some types of waterclosets. A greater rate of flow with substantially the same quietnesscan be provided with the device of Fig. 3 by merely increasing thedifference between the diameter of the plug l6 and the inside diameterof the piece I5, but this reduces the maximum pressure that the devicewill handle quietly, for a much greater overlap is required toeffectively silence the flow when the crevice or clearance is increasedsomewhat.

A second plan for increasing the capacity of the device is to increasethe diameter of the plug 16 and the inside diameter of the piece l5,directly with the desired increase in the rate of flow, keeping theclearance between the parts the same. For example, since the deviceillustrated in Fig. 3 gives a quiet rate of flow of twelve to fourteengallons a minute from high pressure, with the inside diameter of thepiece 15 at one inch, a similarly constructed device wherein the part l5has an inside diameter of two inches would give a quiet rate of flow offrom twenty-four to twenty-eight gallons a minute, provided the diameterof the part I6 is suitably increased to give the same clearance asbefore.

Experiments have indicated that the surface of the plug l6 and theinside surface of the discharge piece !5 may be relatively smoothwithout giving a noisy flow, provided the clearance between the parts bereduced until it is only a few thousandths of an inch, or provided theoverlap is increased by a substantial amount. In general, the smootherthe wall, the less the allowable clearance; consequently, the less therate of flow which can be secured with substantial si-, lence. For manysituations, a throttling device on the order of that illustrated in Fig.3 may prove quite satisfactory with one wall roughened (such as bythreading, knurling, etc.), and the other wall comparatively smooth.This combination gives a quiet rate of flow somewhat in excess of halfthe rate of flow that can be obtained when both walls are roughened, forthe allowable clearance is then only slightly in excess of half theallowable clearance when both walls are roughened.

Referring now particularly to Figs. 4 to 6, modified form of theinvention will be described. In Figs. 4 and 5, the quiet throttling stop502 is shown disposed between a supply pipe NH and a flush valve I04,the connection between the quiet stop i132 and the flush valve I04 beingmade through the customary nipple or tail-piece Hit. The flange i! isused to conceal the exit from the wall of the supply pipe NH. The flushvalve Hi4 may be actuated by the handle I05 to discharge a meteredquantity of water through the discharge tube I06 to the receptacle to beflushed.

In Fig. 6, the stop Hi2 has a casing IH, with the inlet H2 and theoutside-threaded discharge port at H3, the inside of which is ground toreceive the male portion of the usual groundjoint union. A plug l 55 hasa threaded or scored surface to enable it to cooperate with the insidesurface H9 of the throttling barrel. The plug H5 is secured to, and iscontrolled by, the stem H8 to give a desired overlap of the plug Withinthe barrel, according to the desired rate of flow and according to thesupply pressure. The stem i 3 is controlled by the handle I23, beingthreadably secured in the bonnet which is tightly secured in the bonnetopening l M. The packing i2! is held in place by the nut I 22 to preventleakage out around the stem I 98.

The reinforced rubber seat H0 is supported by the back plate or disc Hlagainst bending or cupping when the stop is closed tightly against theseat provided around the mouth of the throat in which the plug H5operates.

The plug H5 has its diameter reduced somewhat for about the first inchof lemth. The lack of full scored diameter in the vicinity of the rubberseat is immaterial to the silent action, as the device is designed togive the correct rate of flow when the stop is opened about one turn, inwhich case about the first inch of the plug is withdrawn. By thisconstruction the area over which the rubber seat member H6 is clamped islessened sufiiciently that only smooth rubber, undistorted by clamping,is presented to the fixed seating surface. This arrangement favorsnonchattering seating and unseating of the valve, as does thesubstantial radius at the exposed corner of the seat member H5.

In proportioning the device of Fig. 6 to give a rate of flow of up tofifteen gallons a minute quietly from a line pressure slightly exceedingone hundred pounds to the square inch, good results were obtained withthe barrel H9 made with an inside diameter of 1 inches, with a clearancebetween the surface of the plug and the inside surface of the barrel ofabout .015 inch, or a total difference of diameter of .030 inch. Underthis condition, a total length of the plug from the surface of the seatH6 of one inch was found to be ample when the scoring or roughening ofthe surfaces H5 and H9 was made by threading thirty-six threads to theinch of standard Whitworth form, except for a flat top about .008 inchwide. With a pressure of one hundred pounds, the desired rate of flow isgiven when the device is open about one turn. For successively lowerinlet pressures, the device is opened greater distances, somewhat asdescribed in connection with the device in Fig. 3. The desired rate offlow may be obtained with substantial silence at any pressure below onehundred pounds by a suitable adjustment.

It is to be noted that the barrel H9 is longer than the plug H5, andthat the scoring of the barrel is continued to the point where it beginsto contract near the outlet H3 to provide for the ground-joint union. Ithas been found that the additional, apparently unused scoring orroughening on the barrel is of material aid in slowing up the annularstream after it leaves the actual throttling restriction. It was foundthat a greater rate of flow can be handled quietly with the additionalroughened surface than can be handled when only that part of the barrelis roughened which can be overlapped by the plug at the setting ofgreatest overlap.

What is claimed is:

1. In a combined throttle and shut-off valve comprising a casing havingan inlet and an enlarged interior, a restricted outlet passageway havinga seating shoulder extending around it, a throttle piece telescopablewithin said passageway and adjustable axially thereof, said throttlepiece and said passageway having cylindrical spaced apart parallel wallsurfaces when the throttle piece is adjusted into said passageway, adisk of relatively rigid material opposed to the end of the throttlepiece, a ring of flexible distortable material clamped between the diskand the throttle piece and adapted to serve as a seating shouldercooperating with the outlet seating shoulder to close communicationbetween the interior and the outlet passageway when the throttle pieceis adjusted the maximum amount into said passageway, said throttle piecehaving a portion of reduced diameter immediately adjacent said disk andring, adapted to provide space for the flexible material when extrudedfrom between the disk and the throttle piece.

2. In a combined throttle and shut-01f valve comprising a casing havingan inlet and an enlarged interior, a restricted outlet passageway havinga seating shoulder extending around it, a throttle piece telescopablewithin said passageway and adjustable axially thereof, said throttlepiece and said passageway having cylindrical spaced apart parallel wallsurfaces when the throttle piece is adjusted into said passageway, aseating shoulder on said throttle piece cooperating with said outletseating shoulder to close communication between the interior and theoutlet passageway when the throttle piece is adjusted the maximum amountinto said passageway, said shoulder including a disc of rigid material,and a ring of flexible distortable material clamped between the disc ofrigid material and the throttle piece, said disc and ring being ofsubstantially greater diameter than the throttle piece, the throttlepiece including a portion of reduced diameter directly adjacent saidring of flexible distortable material, adapted to provide space for saidflexible distortable material as it is distorted when the valve isclosed, and as it is extruded from between the disk and the throttlepiece.

WILLIAM E. SLOAN.

